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Missile Evasion in Total Air War
by Home Fries Introduction Modern anti-air missiles differ greatly in their means of target tracking and engagement, but they all have two things in common: *They all have a limited amount of kinetic energy with which to maneuver (most missiles have their rocket motor burn out after a few seconds, and travel to the target on kinetic energy alone) *They all try to fly a lead pursuit (aka intercept) course when engaging an aircraft Knowing these facts, one realizes that the missile has only so much energy to spare when engaging your aircraft. If you can make the missile spend its energy by maneuvering against you, then the missile may have a more difficult time intercepting you in its terminal phase. Likewise, if you can force a radical course correction in the missile's terminal phase, it is unlikely that the missile (due to its high speed) will be able to make such a correction. There is a simple term used by tactical aviators to describe how best to do this: "Fight Missiles with Aspect." Fight Missiles with Aspect thumb|center|355px| It is primarily because a missile takes lead pursuit on your aircraft that you want to put the missile on your beam (i.e. 90 degrees on either side of your aircraft). This causes the greatest shift in relative motion between you and the missile, and therefore the missile will have to lead your aircraft that much more in order to fly an intercept course. Likewise, give yourself some airspeed so the missile has to lead you even more. Relative Motion vs. Absolute Motion To illustrate the concept of relative versus absolute motion, consider watching a NASCAR race (or any race on an oval track) on television. In all cases, the cars are at a near-constant linear velocity (i.e. they are driving at about 180mph). This is absolute motion. However, your perspective of this changes depending on where the camera is located. If the camera is located on the hood of one of the cars, the relative motion of the car in front of you is near zero. However, if the camera is in the back of the stands, then watching that same car as it goes by at a perpendicular angle (i.e. beaming you) makes its relative motion somewhat faster, though certainly not enough for you to follow by moving your head. Now take that same camera in the stands, and put it right on the side of the track. Watching that same car go by will now give you whiplash as your head and neck move quickly to follow the car as it goes by! Now pretend the missile is the camera. You want the missile looking at you from the side of the track, not from the hood of the guy behind you. Likewise, making the missile follow your maneuvers as it gets closer means a lot more than making it correct while it is still a ways out. Confusing the Missile Beaming a Doppler radar, when used with the combination of active and passive countermeasures, can also have the effect of degrading the return signal, which can also help in defeating the missile. However, AFAIK Doppler shift is not modeled in TAW, so this particular tactic cannot be employed to its fullest potential. However, the use of active Electronic Countermeasures (ECM), aka "Jammers", as well as passive countermeasures (chaff for radar guided missiles and flares for Infrared (IR) guided missiles) can help in spoofing a missile. For the purposes of illustration, I will refer to pumping chaff for defeating a radar guided missile. However, you should substitute flares for chaff if the threat engaging you is IR guided. Since Home-on-Jam (HOJ) is not modeled in TAW, there is no reason not to be in EMCON 5 when nasty things are flying toward you. Start jamming that missile as soon as you know it has your name on it. Chaff should be dispensed when the missile gets closer, as any confusion and possible "hesitation" on the part of the missile has a lot more meaning in the terminal phase, when the relative motion between the aircraft and missile is greater (i.e. the camera is now on the side of the track). Forcing Over-correction Forcing the missile to overshoot is the trickiest part in missile avoidance, and it is also the most important. Everything you have been doing up until now is preparing you to give that missile its own case of whiplash. First, make sure you slow down to corner airspeed (300-350kts in TAW) in order to perform your break maneuver. What you should do next is when the missile gets close, perform a high-g break into the oncoming missile while pumping chaff, and do not end the maneuver until you are on a reciprocal heading. Even better, utilize the vertical as well as horizontal plane by diving into your turn. This maneuver forces the missile that has been leading you at this point to all of a sudden make a drastic course correction in both the horizontal and vertical planes. The dive not only forces to the missile to make two adjustments, but the diving will give you an additional g in tightening your turn ("God's g"). Also, since you turned into the missile, it now has even less time and distance to make the correction! Lastly, because the missile is travelling a lot faster than you are (e.g. Mach 3 versus your Mach 0.5), it needs to pull a lot more g's in order to match your turn circle. In all likelihood, the missile will not come anywhere close to matching your turn circle. As you can imagine, timing and distance are the critical factors in this maneuver. Perform the break too early, and the missile doesn't have to work very hard to make its correction (the camera is still in the grandstands). Perform the break too late, and the missile is close enough to own you regardless of what maneuvers you perform. In real life, pilots need to visually acquire the missile in order to judge distance for when to enter the break. In TAW, countermeasures will be launched automatically once the missile gets close. This is actually good indicator for you to begin your break maneuver as well. Follow-Up You should now be in one piece on a reciprocal heading with the missile having broken lock. Now it's time to reassess your situation. You're low on airspeed, having used up your kinetic energy to defeat the missile, and in all likelihood the bad guy who shot at you is still out there and looking to finish the kill. A common Russian tactic was to ripple fire a R-27R along with a R-27T (the IR guided version of the R-27R) so that the R-27T would clean up the target if the R-27R was spoofed. While this particular instance is unlikely in TAW, especially since the RWR in this case detects IR guided missiles, the point remains that you are not necessarily out of the woods. You have been focusing on defeating a single missile, and as such you need to regain the Situational Awareness (SA) you had before you were shot at. Determine your airspeed, altitude, heading, position, and disposition of the rest of your flight. Is the bandit or SAM site that shot at you still a threat? Are there any threats that took the initiative while you were defensive (a popular tactic in BVR engagements)? Once you have regained SA, you may relax to the level that your situation dictates.